JPS59224007A - Composite superconductive conductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to superconducting conductors, and in particular to composite superconducting conductors having stabilizing materials.

Ultra-high purity aluminum (99.99% or higher) is expected to be used as a stabilizing material for superconducting conductors because its electrical resistance at extremely low temperatures is approximately one-tenth that of high-purity copper (e.g., oxygen-free copper). It is also well known that the technology is becoming more widespread. When aluminum is used as a stabilizing material, it can be used alone, but when it is integrated with a superconducting conductor using solder or other brazing material to form a composite conductor, copper coating is used due to its wettability with solder. The most common method is to use the Even in the latter case, as long as aluminum is used as a stabilizing material, its strength shortcomings are negligible.

However, if the final heat treatment temperature is 550℃ or less, the electrical resistance of aluminum at extremely low temperatures tends to decrease as the treatment temperature increases; becomes soft, which causes another problem.

Therefore, it is difficult to provide sufficient electrical resistance at extremely low temperatures.

An object of the present invention is to provide a composite superconducting conductor having a stabilizing material with high mechanical strength and heat resistance.

According to the present invention, the above object is achieved by constructing a cladding material in which aluminum is coated with oxygen-free copper containing silver as a stabilizing material, and by combining this with a superconducting conductor.

The present invention will be described in detail below based on embodiments shown in the drawings.

Figure 1 shows the silver content, semi-softening temperature of oxygen-free copper, and liquid helium temperature (4,2
FIG. As is clear from this figure, if the silver content is less than 50 ppm, the effect on mechanical strength and heat resistance is insufficient;
000 ppm or more, the effect on mechanical strength and heat resistance is saturated and the electrical resistance at extremely low temperatures becomes too large. Therefore, the silver content is preferably 50 to 20.00 ppm.

Figure 2 shows the heating temperature and 0.2 % proof stress and 4.2 of aluminum parts
FIG. 3 is a diagram showing electrical resistance at °K. As is clear from the figure, the addition of silver improves the 0.2 proof stress and heat resistance.

FIG. 3 shows, in cross section, an embodiment of a composite superconducting conductor in which aluminum is coated with oxygen-free copper containing silver and the cladding material is used as a stabilizing material.

Figure 3a shows a superconductor 3 in a substantially U-shaped groove 5 made of oxygen-free copper.
The groove 5 is closed with an aluminum 1 having an oxygen-free copper coating 2 containing silver, which is made into a composite material with solder 4, and is integrated with solder 4. This is an example in which aluminum having a silver-containing oxygen-free copper coating is used in place of the oxygen-free copper part of the structure, and FIG. In Fig. 3d, a plurality of .J superconducting wires combined by soldering are used as the stabilizing material.

This is an example in which it is housed in an outer sheath 6 made of austenitic stainless steel. In either example, extremely stable superconducting conductors can be obtained due to the improved properties of the stabilizing material due to the inclusion of silver in oxygen-free copper.

That is, since silver white is an element with low electrical resistance and its atomic radius is close to that of copper, even when silver is included, the atomic structure is not disturbed and a uniform solid solution is formed. Therefore, the mechanical strength and heat resistance of the stabilizing material can be improved without increasing the electrical resistance at extremely low temperatures.

[Brief explanation of drawings]

Figure 1 shows changes in the silver content of silver-containing oxygen-free copper, half-softening temperature of oxygen-free copper, and electrical resistance. Figure 2 shows aluminum stabilized with silver-containing oxygen-free copper as a coating. Diagram showing the effect of silver on the properties of the material, Figure 3 C2 No. 3
3C and 3D are cross-sectional views showing examples of superconducting conductors composited with a silver-containing oxygen-free copper coated aluminum stabilizing material. 5- 1... Aluminum 2... Oxygen-free copper coating 3...
・Superconductor 4...Solder 5...U-shaped groove 6...Sheath 6- Sai 3 Roa Sai 3 Day-C Akira 3J-b Akira 3 Figure-l

Claims (1)

[Claims] 1. A superconducting conductor and a stabilizing material, characterized in that the stabilizing material is made of a cladding material in which aluminum is coated with oxygen-free copper containing at least a part of silver. Composite superconducting conductor. 2. The stabilizing material has a silver content of 50 to 2 in the absence of oxygen.
000 ppm, the composite superconducting conductor according to claim 1. 3. The composite superconducting conductor according to claim 1 or 2, characterized in that the stabilizing material is arranged so that the superconducting conductor is juxtaposed. 4. The composite superconducting conductor according to claim 1 or 2, wherein the stabilizing material is arranged so as to surround the superconducting conductor.